Why Flowers Have Color. Achieving a Standard Color in Cosmetic Foundations. More results Generic filters Hidden label. Hidden label. Privacy Policy. Yellow and some white flowers — daffodils, for example — get their color from anthoxanthins. These water-soluble pigments are dispersed throughout the cell sap, and along with carotenoid pigments contribute to autumnal color, as the masking green of chlorophyll empties from leaves. The intensity and hue of flavonoid flower color may change depending on such factors as acidity, temperature, and metabolic activity.
Another major family of color pigments is the carotenoids. These pigments are localized inside cell structures called plastids and produce rich, vibrant yellow and orange colors such as those in sunflowers and the California poppy. Carotenoids also serve as accessory pigments aiding in photosynthesis and in protecting the plant cell from light damage.
Other floral pigments include tannins, which give rise to browns and blacks, betalains, and chlorophyll. Betalains are found in a limited number of plant families, primarily the cacti and related species, and produce a range of colors.
Chlorophyll, the ubiquitous green pigment in plant foliage and the key player in photosynthesis, can color a flower green as well.
Pigment molecules have a limited lifespan, however, and after fertilization, or simply because of aging, they begin to break down. As the degraded molecules accumulate, flower color fades. The pigment anthocyanin gives color to most flowers and fruits.
Anthocyanins are water-soluble pigments in a class of chemicals called flavonoids. A pigment is an organic compound that gives a characteristic color to plant or animal tissue. For example, chlorophyll gives the green color to plant leaves and stems.
Hemoglobin gives blood its red color. Flavonoids, compounds found in many vegetables and fruits, have antioxidant properties. Some flavonoids protect blood vessel walls, some alleviate allergies, and some defend against cancer and viruses.
Others have anti-inflammatory properties. The flower colors of blue, purple, pink, and red come from anthocyanins. Plants produce other pigments, too, like carotene, which makes the orange of carrot roots and the red of tomatoes; chlorophyll, which gives leaves their green color; and xanthophyll, which makes foods like egg yolks and corn yellow.
A common experiment uses the anthocyanins in red cabbage as a pH indicator, because anthocyanins change color depending on their pH. The strip will remain purple if placed in a neutral-pH solution.
Flowers reproduce by having male organs called stamens, loaded with pollen, and female organs named stigmas. The function of the stigma is to receive pollen from another plant of the same species. The bright flower petals attract insects and birds to the nectar or edible pollen produced by the plants.
Yellow flowers are an advertisement for bees, and red attracts birds. Some flowers change color during the growing season. For example, forget-me-nots change from pink to blue. Larkspur, or delphiniums, change color, too. Color shifts send a signal to insects that a flower has aged and is past pollination.
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